Pacific Insects 10 (1): 47-77 10 May 1968 RHYNCHOPHORINAE OF SOUTHEASTERN POLYNESIA1 2 (Coleoptera : Curculionidae) By Elwood C. Zimmerman BISHOP MUSEUM, HONOLULU Abstract: Ten species of Rhynchophorinae are recorded from southeastern Polynesia, including two new species of Dryophthorus from Rapa. Excepting the latter, all the spe­ cies have been introduced into the area and most are of economic importance. Keys to adults and larvae, notes on biologies, new distributional data and illustrations are pre­ sented. This is a combined Pacific Entomological Survey (1928-1933) and Mangarevan Expedi­ tion (1934) report. I had hoped to publish the account soon after my return from the 1934 expedition to southeastern Polynesia, but its preparation has been long delayed be­ cause of my pre-occupation with other duties. With the exception of two new endemic species of Dryophthorus, described herein, all of the Rhynchophorinae found in southeastern Polynesia (Polynesia south of Hawaii and east of Samoa; see fig. 1) have been introduced through the agencies of man. The most easterly locality where endemic typical rhynchophorids are known to occur in the mid- Pacific is Samoa where there are endemic species of Diathetes. (I consider the Dryoph- thorini and certain other groups to be atypical Rhynchophorinae). West of Samoa the subfamily becomes increasingly rich and diversified. There are multitudes of genera and species from Papua to India, and it is in the Indo-Pacific where the subfamily is most abundant. Figure 2 demonstrates the comparative faunistic developments of the typical rhynchophorids. I am indebted to the British Museum (Natural History) for allowing me extensive use of the unsurpassed facilities of the Entomology Department and libraries and to the Mu­ seum of Comparative Zoology, Harvard University, for use of the library. Photographs 22 and 26 are from the British Museum (Natural History), and all of the other photo­ graphs were generously prepared by my friend Dr David Kissinger. LIST OF THE RHYNCHOPHORINAE OF SOUTHEASTERN POLYNESIA DRYOPHTHORINI 1. Dryophthorus rapaae Zimmerman, n. sp. Rapa ; endemic. 1. Rhynchophora of Southeastern Polynesia, part 15. 2. This is part 16 of a series of reports resulting from the project "Pacific Island Weevil Stu­ dies" made possible by National Science Foundation Grant G-18933, which I gratefully ac­ knowledge. ASIA > Midway ' • HAWAII (^FORMOSA MARIAN AS Wake O .o,. PHILIPPINE •'Guam .MARSHALL / %;4 . -..CAROLINE BORNEO <pQ / \ • .'.,•. ;;-\, . XV ^y. -Palau ' '.Fanning i'.GILBERT PHOENIX " . Y^UINEA^^9 "^SOLOMON '--ELLICE" ^ JAVA ^ \ '; '• . .SAMOA'' NEW ^: F|j|.- SOCIETY— HEBRIDES ') •ol---:. • .pOOK'tah NEW ^-. ' OTONGA CALEDONIA" * * . % AUST Norfolk Rapa '".Lord Howe /Kermadec NEW < /ZEALAND FASMANIAV^ ^Chatham Fig. 1. Map of the Pacific showing the southeastern Polynesian trian 1968 Zimmerman: Rhynchophorinae of Polynesia 49 ll . ETH INPAC PAL AM Fig. 2. A graph demonstrating the comparative gene­ ric representation of the typical Rhynchophorinae in the major faunistic regions. ETH=Ethiopian, 39 genera. INPAC=Indo-Pacific, 59 genera. PAL=Palearctic, 1 ge­ nus. AM=America, 21 genera. (Data modified from Co- leopterorum Catalogus.^) 2. Dryophthorus perahuae Zimmerman, n. sp. Rapa; endemic. 3. Stenommatus musae Marshall. Society Islands; widespread in the Pacific. RHYNCHOPHORINI Sphenophorina 4. Rhabdoscelus obscurus (Boisduval). Society, Austral, Gambier and Marquesas Islands; widespread in the Pacific. 5. Cosmopolites sordidus (Germar). Society and Marquesas Islands; nearly tropicopoli- tan. 6. Poly tus mellerborgi (Boheman). Society, Marquesas, Gambier and Pitcairn Islands; nearly tropicopolitan. Sitophilina 7. Diocalandra taitense (Guerin-Meneville). Line, Society, Tuamotu and Marquesas Is­ lands ; widespread in the central Pacific. 8. Sitophilus linearis (Herbst). Society Islands; nearly tropicopolitan. 9. Sitophilus oryzae (Linnaeus). Society Islands ; nearly cosmopolitan. 10. Sitophilus zeamais (Motschulsky). Society Islands; nearly cosmopolitan. KEY TO GENERA OF RHYNCHOPHORINAE FOUND IN SOUTHEASTERN POLYNESIA A. Key to Adults 1. Antennal funicle 4-segmented; pygidium normally almost concealed, but if exposed it displays a single, medial, conspicuous sulcus which extends from base to apex; the true 4th tarsal segment (" cryptotarsite ") more strongly developed than normal for Curculionidae and tarsi distinctly 5-segmented; scutellum concealed; metepisternum 50 Pacific Insects Vol. 10, no. 1 concealed beneath elytra (Dryophthorini) 2 Antennal funicle 6-segmented; pygidium always strongly exposed, never with a single medial sulcus that extends to apex but at most with a sulcus (appearing double) at extreme base only (as seen in normal position) ; the true 4th tarsal segment small and inconspicuous, enclosed within the 3rd segment (never projecting beyond 3rd segment) and tarsi thus appearing 4-segmented; scutellum and metepisternum conspicuously exposed (Rhynchophorini)... 3 2(1). Rostrum stout, much shorter than pronotum; lower edges of eyes distant from pro­ notum and widely separated beneath Dryophthorus Rostrum comparatively slender, about as long as pronotum; lower edges of eyes very close together or contiguous beneath and there normally hidden beneath edge of prosternum; minute species about 2 mm long Stenommatus 3(1). Antennal scrobe with a posterior vertical extension that extends ventrad in front of eyes (Sitophilina)... 4 Antennal scrobe entirely horizontal (Sphenophorina)... 5 4 (3). Pygidium with a dorsal, basal, medial sulcus containing a narrow carina (usually easily seen extending a short distance caudad of apices of elytra when pygidium is in normal retracted position at rest and very prominent beneath elytra or when pygidium is extended, and because of the included carina it may appear as a double sulcus); setae scattered over surface of pygidium and not forming prominent lines; mesocoxae more narrowly separated than procoxae; ventrite 1 shorter at its nar­ rowest point behind metacoxa than ventrite 2 Sitophilus Pygidium without such a sulcus and with erect setae forming a median crest and a line at each side behind middle; mesocoxae more distantly separated than procox­ ae ; ventrite 1, at its narrowest point behind metacoxa, distinctly longer than ven­ trite 2 Diocalandra 5 (3). Tibiae uncinate and mucronate, the mucrones strong; claw segment of tarsus with articulating cavities opening mesally into one another and claws basally approxi­ mate; length, excluding head and rostrum, less than 5.0 mm Polytus Tibiae uncinate only, mucrones obsolete; tarsal claw segment with sclerotized exten­ sions from dorsum and venter which curve around apex of segment thus enclos­ ing it and distinctly separating the bases of the claws; length, excluding head and rostrum, over 7.0 mm 6 6 (5). Third tarsal segment hardly broader than 2nd, and 4th segment inserted in it distad of middle; scutellum expanding caudad; distal setose part of antennal club broad­ ly cone-shaped; hind femora reaching behind elytra to apex of pygidium...Cosmopolites Third tarsal segment much broader than 2nd, more than 2 or 3 X as broad, and 4th segment inserted basad of its middle; scutellum narrowing caudad; distal setose part of antennal club V-shaped in cross section; hind femora not reaching apex of elytra .....,..................,.........,....,...,, . Rhabdoscelus B. Key to Laryae 1. Caudal (9th) abdominal segment with a pair of fleshy processes; posterior pair of se­ tae on postmentum separated subequally to middle pair of setae; frons with only 4 pairs of setae; meso- and metathoracic postdorsa with only 2 setae; spiracles on middle abdominal segments minute, hardly discernible, non-functional (Dryophthorini)... 2 Caudal (9th) abdominal segment without fleshy processes; posterior pair of setae on postmentum separated by less than 1/2 the distance separating the middle pairs of setae; frons with 5 pairs of setae; meso- and metathoracic postdorsa with 3 or 4 1968 Zimmerman: Rhynchophorinae of Polynesia 51 setae; spiracles on middle abdominal segments all distinct and well developed (Rhynchophorini)... 3 2(1). Head with frontal setae 4 and 5 long and subequal; inner surface of mandible with a granular area; abdomen with functional spiracle on segment 8 only; length of mature larva greater than 3.0 mm Dryophthorus Head with frontal setae 4 and 5 unequal, 4 minute, 5 long; without a granular area on inner surface of mandible; abdomen with functional spiracles on segments 1 and 8; length of mature larva less than 2.75 mm Stenommatus 3(1). Epipharynx with 2 simple anterolateral setae; sensilla on epipharynx very small, peg­ like ; postdorsum of meso- and metathorax with 3 setae; larvae small, subglobular, infesting seeds and cereals Sitophilus Epipharynx with 3 or more anterolateral setae, some of these setae branched; sen­ silla on epipharynx developed as pores; postdorsum of meso- and metathorax with four setae; larvae infesting banana, palms, sugarcane and other grasses 4 4 (3). Abdominal segments 1 to 7 without discernible spiracles (Polytus) or the spiracles very small, without discernible air tubes (Cosmopolites); seta on epipleurum of me­ tathorax distinctly shorter than on epipleurum of mesothorax 5 Abdominal segments with spiracles present, occasionally small, but air tubes are well developed; seta on epipleurum of metathorax subequal in length to that on epipleu­ rum of mesothorax 6 5 (4). Abdominal segments 1 to 7 without discernible spiracles ; thoracic spiracle not curved, the air